Composite signaling system



Oct. 9, 1928. 1,687,432

H. W. DRAKE COMPOSITE SIGNALING SYSTEM,

Filed Sept. 23, 1925 TT I I- II i|||-- 3 a n H H II I \I (u gwuentor .fiQ/J/f Wfll'aie Patented 0a. 9,; 1928.

UNITED STATES PATENT OFF-ICE.

HERBERT 'W. DRAKE, OF EAST ORANGE, NEW JERSEY, ASSIGNOB.TO THE WESTERN UNION TELEGRAPH COMPANY, OF NEW YORK, N. Y., A] CORPORATION OF NEW- YORK.

comrosrrr': SIGNALING SYSTEM.

of the present invention is to provide an improved method of signaling over a composite circuit which will enable a lineman to signal the central oflice from any point along the line where he may be engaged ,so that he may then tap his portable telephone on the line and report to orreceive orders directly from the wire chief. It has heretofore been proposed to signal the central oflice by sending impulses from an induction coil and battery carried by the lineman to operate a neutral relay locate at thev central oflice. This equipment was rather heavy and addedvery materially to the weight which must necessarily be carried by the lineman.

My present invention superposes a, signaling current upon the lines at the central station,

the circuit arrangement being such that the relay, or indicating device is normally unaffected by the signaling current'but responds immediately when the lineman unbalances the system by connecting to the line at any point.

i In the following detailedde'scri tion, I

' rawing shall refer to the accompanying which'illustrates in a conventional manner one embodiment of my invention.

- 1 and 2 are the lines which are used in separate telegraph circuits to carry Morse signals. A composite set within the dotted rectangle 3 comprising the usual arrangement of inductances and condensers, is interposed for the purpose of connecting the telephone instruments or the signaling gen-- erator circuit. The latter comprises an alternating current generator 6 of 133 cycles or other suitable frequency, a reactance set or artificial line 7 which is adjusted to exactly balance the characteristics of the lines 1 and" 2, the composite set 3, and the primary coils of a transformer 8, the secondary coils being connected to a relay 9 or other electro-respousive device tuned to the frequency of the generator 6'. hem-therefore, the switch 10 is thrown to the right, to superimpose the signaling current upon the lines 1 and 2, the current I from the generator will divide equallynbetwcen the main .line circuit 1, 2 and the artificial line 7 Inasmuch as equal and opposite currents are impressed respectively upon the primary coils of the transformer 8, no current will flow in the secondary circuit of the transformer and the relay'9 will be unaffected;

If now a lineman disturbs the balance. between the main and artificial lines, which hev may do without interference with the Morse signals on the lines, by connecting his portable set across the lines as indicated at points 12 and 13, a greater current will then flow on one side of the transformer than on the other and, the resultant current in the secondary circuit will operate the relay or other indicating device 9., I have indicated within the dotted line rectangle 14 the usual linemans set including the teleph'onetransmitter and receiver. 15, condenser 16 and switch 17.

As soon as an indication is received at the central office on the relay or indicator 9,'the w'ire' chief .or attendant throwsthe'switch 10 over to the left, therebydisconnecting the signaling generator and connecting the telephone apparatus 4 to the lines. The lineman Q5 is then enabled to converse with the wirechief or attendant at the central ofiice. As soon as the lineman disconnects his portable set from the lines, the attendant at the central oflice throws the switch 10 back to the right hand x position, thereby re-establishing the connection between source "of signaling cur rents and the lines.

I have described thissignaling system as especially intended for use by linemen in as si naling to the central oflice, yet it is ap-. phcable to other purposes, as for instance, to provide an indicationat-the central oflice when excessive leakage develops on the line wires. Other engineers.

I claimpurposes will readily occur to 1. In .a composite signaling system, a

transmission line, a telephone apparatus, a

to connect at will either said telephone apparatus or one of said sections to said trans- "local circuit comprising two sections, means section to compensate for the connection of said first section to line whereby neutral points are established between said sections, means to apply an alternating signaling current at said neutral points for transmlssion over said line, a transformer in said local circuit having primary coils disposed upon opposite sides of one of said neutral points, and an electro-responsive device responding to signaling frequency currents connected to the corresponding secondary coils of said transformer. I

2. In a composite signaling system, a transmission line, the conductors of which are adapted to form separate telegraph circuits, alocal balanced circuit having two sections, one section including means to compensate for the characteristics of the line whereby neutral points are established at the junction of the sections when the local circuit is connected to the line, means to aply signaling currents at said neutral points or transmission over said line, a local telephone apparatus and means to statically connect to the line at will either said local Icircuit or said local telephone apparatus.

3. In a composite signaling system, a

transmission line, the conductors of which are adapted to form separate telegraph circuits, a local balanced circuit having two sections, one section including means to compensate for the characteristics of the line whereby neutral points are established at the junction of the sections when the local circuit is connected to theline, means to apply signaling currents at said neutral points for transmission over said line, a. transformer having a primary coil included in each section, an electrically actuated device connected to corresponding secondary-coils of said transformer and adapted to be actuated Joy the signaling frequency currents when the balanced condition of said local circuit is disturbed'by an abnormal condition of the line, a local telephone apparatus and means to statically connect to the line at will either said local circuit or said local telephone apparatus.

4.'In a composite signaling system, a

transmission line, the conductors of which are adapted to form separate telegraph circuits, a local balanced circuit having two sections, one section including means to compensate for the charactenstlcs of the line whereby neutral points are established at the nected to corresponding secondary coils of said transformer and adapted to be actuated by the signaling frequency currents when the balanced condition of said local circuit is disturbed, a portable telephone apparatus provided with means for connectingto the.

line at'any desired points to thereby cause an unbalanced condition of said local circuit,

a local, telephone apparatus and means to statically connect to-the line at will either said local circuit or said local telephone apparatus.

5. In a composite signaling systein; a transmission line having its conductors forming separate telegraph circuits, a local circuit including two primarycoils of a transformer switching means for connecting said circuit to said line, means in said local circuit including one of said primary coils to compensate for the connection of the line when connected thereto, whereb neuan points maybe established to divi e said Y local circuit into two sections, one of said neutral points being at the junction between said coils, means to apply alternating signaling currents at said neutral points, an

electromagnetic device connectedto the secondary coils of said transformer and responsive to the frequency of, said signaling currents only when said balanced (imdition becomes unbalanced, a telephoneapparatus, and a switch device operable at will to connect said telephone apparatus to the line and to simultaneously disconnect said local circuit from the line.

In testimony whereof I afiix m HERBERT W.

signature. I RAKE. 

